The middle wedge which is used to flatten the hair as it enters the
mortise and to evenly distribute the hairs, it is formed so that the
hairs on the playing side are turned over again (the photo shows a cello
bow).

Hairs are shown in the mortise at the head of the bow.

Hairs that are in the hair block at the head of the bow are fastened with a wedge only and never glued!